I'm currently writing a toy compiler targeting Java bytecode in the translation.
I would like to know if there is some kind of catalog, maybe a summary, of various simple peephole optimizations that can be made in the emitted bytecode before writing the .class file. I actually am aware of some libraries that have this functionality, but I'd like to implement that myself.
You are aware of Proguard? http://proguard.sourceforge.net/
This is a great bytecode optimizer which implements a lot of optimizations. See the FAQ for a list: http://proguard.sourceforge.net/FAQ.html
I'm sure you can further look into the source code to understand how they are implemented.